Measuring cleanliness in industrial, food processing, food service, health care and other settings is important for maintaining good hygiene and sanitation. For example, the surfaces of equipment used for food handling, storage or processing can be a major source of microbial and allergen contamination. Microbial contamination can lead to decreased shelf life of products and, if pathogenic, transmission of disease. Allergen contamination can cause adverse reactions in sensitive people including hives, anaphylaxis and death.
Microbial culturing can determine the presence of microorganisms. Culturing is, however, time consuming and, as a result, the necessary “real time” feedback to sanitation and food preparation personnel may not be available. It is, therefore, possible that food exposed to surfaces that are later found to contain potentially harmful microorganisms could enter the food supply.
Rapid and efficient test methods and devices are available for the detection of contamination on surfaces. Some of these methods do not detect microbes directly but instead use markers such as adenosine triphosphate (ATP) that are indicative of the presence of microbes or residual food contamination of a surface. For example, those described in U.S. Pat. No. 6,055,050 (Photometer and Test Sample Holder for use therein, Method and System) issued Apr. 25, 2000; and U.S. Pat. No. 6,180,395 (Reagent Chamber for Test Apparatus and Test Apparatus), issued Nov. 30, 2001, both of which are incorporated herein by reference. A commercially available apparatus that detects ATP is the POCKETSWAB-PLUS (POCKETSWAB is a registered trademark of Charm Sciences, Inc. of Lawrence, Mass.), which rapidly and efficiently detects ATP on surfaces. The POCKETSWAB detects ATP by emission of luminescence (light) from the reaction of luciferin and luciferase in the presence of ATP. The luminescence can be measured using a luminometer.
Specific allergen tests are typically in the ELISA (enzyme linked immunosorbent assay) format and require 30 minutes or more to obtain a result. Historically, ELISA allergen tests were more sensitive than ATP tests for detecting allergenic food residues. Recently, however, highly sensitive ATP detection assays and systems, particularly single service ATP detection assays, have been used to rapidly screen a surface for food residue at a level of allergen test detection that is consistent with sensitivity of available ELISA methods. Such a test is described in U.S. Pat. No. 7,132,249, issued Nov. 7, 2006 (Method of Determining Allergenic Food on Surfaces), incorporated herein by reference. For tests that detect certain allergens, such as peanut allergens, regulations require sensitivity at particular levels, such as 5 parts per million peanut allergen. The ALLERGIENE (ALLERGIENE is a registered trademark of Charm Sciences, Inc., Lawrence, Mass.) ATP test detects ATP with sensitivity adequate to be used as an indicator for potential allergen contamination.
With increased sensitivity to ATP the problem of interference from background noise may increase. Minimizing or eliminating this problem can help avoid false results and provide better signal to noise ratios in not only highly sensitive ATP systems but also less sensitive ATP systems. Similarly, luminescence based tests, other than those relying on the luciferin/luciferase ATP reaction, may also benefit from methods and devices for reducing background noise.
Therefore, Applicants desire a system and method for hygiene monitoring without the drawbacks presented by the traditional systems and methods.